The correct option is C Kerala
Coastal plains are flat areas that can be found around the sea in states like Kerala, Goa and others. The northern plains can be found in states like Bengal, Haryana, Bihar and others. The mountain regions are situated in the Northern India like Kashmir, Uttarakhand, Sikkim and others. Plateau regions in India are found in states like Jharkhand, Chhattisgarh and others.